JPH04139281A - Coating composition and coating film formation therefrom - Google Patents

Abstract

PURPOSE:To provide the title composition capable of giving coating films excellent in finishability and recoatability, etc., consisting of a curing resin composition comprising a base resin containing both hydroxyl and carboxyl groups, aliphatic polyepoxide curing agent and specific catalyst. CONSTITUTION:The objective composition consisting of a curing resin composition comprising (A) a base resin containing both hydroxyl and carboxyl groups (pref. 1000-100000 in number-average molecular weight, 200-2000 in hydroxyl group equivalent and <=120 deg.C in softening point), (B) an aliphatic polyepoxide curing agent (e.g. butanediol diglycidyl ether), and (C) as catalyst, metal.beta- diketone chelate [pref. tris(acetylacetonato)aluminum] and/or quaternary ammonium hydroxide (e.g. tetramethyl ammonium hydroxide).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel coating composition and coating film forming method.

[Prior Art and its Problems] Conventionally, there has been a demand for improvements in finished appearance, coating performance, etc. in top coat films, particularly in top coat films for automobile exterior panels. In addition, there is a strong demand for the development of low-temperature curing coatings for the purpose of reducing energy costs and for the purpose of making it possible to apply the same paint to the exterior of automobiles where steel plate base materials and plastic base materials are integrated. There is.

The current mainstream paints for automobiles are thermosetting acrylic resin/melamine resin type and thermosetting polyester resin/melamine resin type, but these paints are close to the limit in terms of high level of smoothness, and There is also room for improvement in the performance of various coating films. Further, there is a problem that the low temperature curing property is not sufficient.

The present applicant has proposed JP-A No. 2003-231002 as a coating material with excellent low-temperature curing properties.
An automobile paint composition was proposed in Japanese Patent No. 160879. The paint is a silicone paint composition made by blending a metal chelate compound into a copolymer containing a polysiloxane macromonomer containing a silanol group and/or an alkoxysilane group and a vinyl monomer containing an oxirane group as monomer components. If this product is applied to both a metallic base coat (paint containing aluminum flake pigment) and a clear top coat, and a two coat, one bake method is used to finish the painting, the metallic base coat is the clear top coat. This has the disadvantage that the orientation of the aluminum flake pigment changes due to the aluminum flakes, making it impossible to obtain a paint film with aluminum luster (metallic feel, "sparkle, whiteness"). The disadvantage of using a polyester resin/melamine resin type is that the clear top coat begins to harden before the metallic base coat begins to harden, resulting in defects such as wrinkles and wrinkles in the paint film. Additionally, there were problems such as paint film staining and environmental pollution due to condensates (formalin, etc.) generated during baking.

In addition, when a defect occurs in the finished coating, the same type of metallic base coat and clear top coat are usually recoated to repair the defective part. There also remained the problem that adhesion between the films (top clear coat and recoated metallic base coat) was insufficient.

[Means for Solving the Problems] As a result of extensive research in order to eliminate the above-mentioned drawbacks, the present inventors have developed a base resin containing hydroxyl and carboxyl groups, an aliphatic polyepoxide curing agent, and a metal/β-diketone chelate. and/or a coating composition containing a quaternary ammonium hydroxide catalyst has excellent low-temperature curability, and by using this as a colored base coat and further forming a specific clear top coat on the base coat,
It was discovered that a coating film with excellent finishing properties, recoatability, etc. could be provided, and the present invention was completed.

That is, the present invention comprises the following components (A) a base resin containing hydroxyl and carboxyl groups, (B) an aliphatic polyepoxide curing agent, and (C) a metal.
A coating composition characterized by containing a catalyst of β-diketone chelate and/or quaternary ammonium hydroxide as a cured resin composition, and a multi-layer top coat formed by sequentially forming a colored base coat and a clear top coat on a material. In the film, the colored base coat is combined with the following components (A) a base resin containing hydroxyl and carboxyl groups, (B) an aliphatic polyepoxide curing agent, (C) a catalyst for metal/β-diketone chelate and/or quaternary ammonium hydroxide, and (D) ) A colored coating composition containing a colored pigment of metal flake powder and/or mica powder as an essential component, and the clear top coat is formed from the following component (E) silanol and a hydrolyzable group directly bonded to a silicon atom. The present invention relates to a method for forming a coating film, which is characterized in that it is formed using a clear coating composition containing as essential components a base resin containing at least one selected group, a hydroxyl group and an epoxy group, and (F) a curing catalyst.

First, the coating composition of the present invention will be described.

As the hydroxyl group- and carboxyl group-containing base resin used in the coating composition of the present invention, conventionally known resins can be used without particular limitations. The base resin has a number average molecular weight of 1.
000-100.000, hydroxyl equivalent 200-2.0
00 and a softening point of about 120° C. or less.

The carboxyl group in the base resin is not particularly limited as long as it is in the amount necessary to act as a catalyst for the above-mentioned reaction system or in the amount necessary for making it aqueous, but it may be contained so that the acid value is 5 to 100. It is preferable to let Further, the base resin can have a phenolic or silanol hydroxyl group in addition to the hydroxyl group and the carboxyl group.

The base resin includes hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, polycaprolactone diol mono(meth)acrylate, and polyoxyethylene glycol mono(meth)acrylate. : Carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl acrylate, itaconic acid: Furthermore, if necessary, methyl (meth)acrylate, ethyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, etc. ) acrylate,
2-ethylhexyl (meth)acrylate, acrylonitrile, acrylamide, styrene, vinyltoluene,
By copolymerizing with other radically polymerizable unsaturated group-containing monomers that do not have functional groups that react with hydroxyl groups and carboxyl groups, such as vinyl acetate, 1-propyl vinyl ether, n-butyl vinyl ether, and methoxyethyl vinyl ether. You can use what you get.

The copolymerization reaction can be carried out by any known solution polymerization or dispersion polymerization method. In solution polymerization, it is preferable not to use a high boiling point alcohol as a solvent since it inhibits curability.

In addition to the above-mentioned base resins, trimethylolethane, trimethylolpropane, pentaerythritol,
Polyol components such as glycerin, ethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, 1,6-hexanediol and (anhydrous) phthalic acid, isophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, adipic acid Polyester resins obtained by polycondensation with polycarboxylic acid components such as (anhydrous) trimellitic acid: those obtained by modifying said polyester resins with fatty acids or epoxy resins, and acrylic-grafted modified polyester resins: bisphenol-epichlorohydrin type epoxy resins. A modified epoxy resin obtained by adding an acid anhydride to an esterified product or an etherified product can be used.

In the present invention, since a coating film with excellent cosmetic properties and weather resistance can be obtained, it is preferable to use an acrylic copolymer in which a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and other monomers are copolymerized as necessary. preferable.

In combination with the above base resin, carboxyl groups such as polytetramethylene glycol, bisphenol A/ethylene oxide adduct, polycaprolactone polyol, polycarbonate diol, polyurethane polyol, vinyl alcohol (co)polymer, styrene-allyl alcohol copolymer, etc. Polyol resins that do not contain polyols can also be used.

The aliphatic polyepoxide curing agent has an average of two or more aliphatic epoxy groups in one molecule. When the number of epoxy groups is less than 2 on average, curability decreases. The curing agent also generally has a number average molecular weight of about 100 to about 100.00.
0, preferably in the range of about 110 to about 20,000, and a softening point of about 130°C or less, preferably about 115°C
Those with a number average molecular weight of less than about 100 are difficult to obtain, while those with a number average molecular weight of more than about 100,000 are not so preferable because the smoothness of the coated surface deteriorates. If the point is higher than about 130°C, the smoothness of the coating film tends to deteriorate.

As the aliphatic polyepoxy curing agent, conventionally known ones can be used, but from the viewpoint of weather resistance, those excluding novolac type polyepoxy and epichlorohydrin-bisphenol type polyepoxy are preferred. Preferred curing agents include butanediol, for example. diglycidyl ether, 1.6
-Hexaneshiol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, etc. Polyglycol ether type epoxy compounds such as, polycarboxylic acid ester type epoxy compounds such as phthalic acid diglycidyl ester, isocyanurate type epoxy compounds such as triglycidyl isocyanurate, epoxidized fatty acid esters such as epoxidized soybean oil, etc. , an isopolymer of an epoxy group-containing radically polymerizable unsaturated monomer (e.g., glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, etc.) or a copolymer of this monomer and the above-mentioned other radically polymerizable unsaturated group-containing monomer, etc. can be mentioned.

The amount of the curing agent used is not particularly limited, but is approximately 16 to 50% by weight of the width of one composition (base resin, curing agent, catalyst) and (total of hydroxyl groups and carboxyl groups of the base resin)/(epoxy group of the curing agent). ) is preferably in the range of about 0.5 to 1.5.

If the equivalence ratio is less than about 0.5, there will be a large amount of epoxide homopolymerized, while if the equivalence ratio is more than about 1.5, the parent wood base of the coating will be strong (and the performance such as water resistance will be poor). Unfavorable 6 metal/β-diketone chelate catalysts include AI2, T
Examples include chelates of metals such as 1, V, Fe, Zn, Zr, and Sn and β-diketones such as ethyl acetoacetate, trifluoroacetylacetone, benzoylacetylacetone, and dibenzoylacetylacetone. Among these, tris(acetylacetonato)aluminum is most preferred.

Also, as a quaternary ammonium hydroxide catalyst, Teha, -
Formula a: [R'R"R"R'N"] QHe can be used. In the above formula, R1, R2,
R3 and R4 each represent a hydrocarbon group, which may be the same or different, and the hydrocarbon group may be substituted with a hydroxy group.

Specific examples of quaternary ammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetraisoamylammonium hydroxide, and tetradodecyl. Ammonium hydroxide, methyltriethylammonium hydroxide, ethyltrimethylammonium hydroxide, tetradecyltrimethylammonium hydroxide, monohydroxyethyltrimethylammonium hydroxide, monohydroxyethyltriethylammonium hydroxide, dihydroxyethyldimethylammonium hydroxide, dihydroxyethyldiethylammonium hydroxide, trihydroxyethylmonomethylammonium hydroxide, trihydroxyethylmonomethylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, benzylmethyldiethylammonium hydroxide, cyclohexyltrimethylammonium hydroxide, etc. grade ammonium hydroxide.

When used in water-based form, ammonium hydroxide can easily disperse the base resin and curing agent in water, giving the paint excellent storage stability and forming a coating film with excellent water resistance, corrosion resistance, etc. It has the advantage of being particularly suitable for use. Furthermore, when using an organic solution type, it is preferable to use it as a methanol solution.

The metal/β-diketone chelate and quaternary ammonium catalyst are generally about 0.01 to about 10% by weight, preferably about 0.01 to about 7% by weight, based on the total amount of the base resin, curing agent, and catalyst. %, more preferably in the range of 0.1 to 5% by weight.

The coating composition of the present invention is usually used in an organic solution type or an aqueous type. As #a solvents used in organic solution type,
Solvents that are substantially inert with components such as the base resin, curing agent, and catalyst, such as ester-based, alcohol-based, ether-based, aromatic-based, and aliphatic hydrocarbon-based solvents, can be used. Moreover, an aqueous type can be obtained by neutralizing the carboxyl group for the base resin with a basic compound and dispersing it in water. Suitable basic compounds include triethylamine, jetanolamine, aminomethylpropanol, dimethylamine ethanol, and the like.

The coating composition of the present invention may include, for example, polytetramethylene glycol, bisphenol A,
Polyol resins that do not contain carboxyl groups, such as ethylene oxide adducts, polycaprolactone polyols, polycarbonate diols, polyurethane polyols, vinyl alcohol (co)polymers, and styrene-allyl alcohol copolymers, can also be blended. In addition, for the purpose of curing the coating film at lower temperatures, phenolic compounds (such as catechol) and silanol compounds (
(e.g. diphenylsilanediol), metal chelate compounds (e.g. AJ2, Ti, V, Fe, Zn, Zr,
(Co-)catalysts such as chelates of metals such as Sn and β-diketones such as ethyl acetoacetate, trifluoroacetylacetone, and dibenzoylacetylacetone) can also be used. The (co-)catalyst is usually used in an amount of about 0.00 parts by weight based on 100 parts by weight of the base resin and curing agent.
It can be blended in an amount of 0.01 to about 10 parts by weight.

Furthermore, the coating composition of the present invention may contain colored pigments (for example, titanium white, carbon black, aluminum,
red iron, etc.), extender pigments (e.g. clay, talc, silica, polymer particles, etc.) and other paint additives (
(e.g. pigment dispersants, anti-cissing agents, fluidity regulators, etc.)
It can also include.

The method of forming a coating film using the coating composition of the present invention is not particularly limited, and for example, it may be applied to the surface of a substrate by means such as electrodeposition coating, spray coating, dip coating, roller coating, or brush coating, and then dried. This can be done by Although there are no particular limitations on the coating film thickness, a range of 10 to 100 P is usually considered sufficient. The drying time of the paint film is usually about 130
C. for about 30 minutes, and at about 190.degree. C. for about 10 minutes. The base material to be coated is also not particularly limited, but preferably steel, aluminum, alumite, copper, plated steel in which the surface of steel is plated with zinc, tin, chromium, aluminum, etc., or the surface of steel is plated with chromic acid,
It can be applied to a wide range of metals, including those treated chemically or electrolytically with phosphoric acid.

In the coating composition of the present invention, the carboxyl group in the base resin and the quaternary ammonium hydroxide or metal β
- Functional group-like reaction of diketone chelate with hydroxyl groups in the base resin and epoxy groups in the curing agent in the presence of a catalyst,
It is thought that almost no reaction occurs at temperatures around room temperature, and when baked at temperatures around 130°C, reactions similar to those of the functional groups proceed rapidly.For this reason, the coating composition of the present invention has particularly good storage stability and It is thought that the effect is that the coating film has excellent low-temperature curability. Furthermore, since condensates such as formalin are not generated during the curing of the coating film, there are no problems such as coating peeling or environmental pollution.

Next, the coating film forming method of the present invention will be described.

The coating film forming method of the present invention involves coating a material with a colored coating composition to form a colored base coat, and then applying a clear coating composition to the uncured coating film of the colored base coat or the coating film cured by heating. , can be carried out by heating.

Metal flake powder used in colored paint compositions includes:
aluminum flakes, nickel flakes, copper flakes,
Examples of the mica powder include brass flakes and chrome flakes, and examples of the mica powder include pearl mica and colored burl mica. The amount of these powders to be used can be selected as appropriate depending on the required use, but it is usually 1 to 30 parts by weight, based on the total of 100 parts by weight of the base resin and crosslinking agent.
Preferably, 2 to 20 parts by weight are mixed.

In the present invention, the clear top coat is a base resin containing a silanol group and/or a hydrolyzable group directly bonded to a silicon atom, a hydroxyl group, and an epoxy group (hereinafter abbreviated as "base resin for top coat") and cured. It is formed from a clear coating composition containing a catalyst as an essential component.

The hydrolyzable group possessed by the above base resin for top coat is
It is a residue that generates a hydroxysilane group by hydrolysis in the presence of water, and examples include C1~ alkoxy groups: phenoxy group, tolyloxy group, paramethoxyphenoxy group,
Aryloxy groups such as varanitrophenoxy group and benzyloxy group: acetoxy group, propionyloxy group,
Acyloxy groups such as butanoyloxy group, benzoyloxy group, phenylacetoxy group, formyloxy group and -N(R'), -0N(R'La, -0N=C(R'
lz, -NR8COR5 (in the formula, each R5 is the same or different and is an alkyl group of 01 to 8, an aryl group,
It represents an aralkyl group, and R6 represents H, C, ~8 alkyl group. ), etc.

As the base resin for the top coat, for example, ■ hydroxyl group-containing resin (■), epoxy group-containing resin (R), resin (III) containing a silanol group and/or a hydrolyzable group directly bonded to a silicon atom; Resin mixture containing three components (hereinafter abbreviated as "resin ■"), ■ Epoxy group-containing resin (■), resin containing a silanol group and/or a hydrolyzable group directly bonded to a silicon atom (11) a two-component resin mixture, and the resin (n
) and resin (III), or a resin mixture containing a hydroxyl group in either or both of them (hereinafter abbreviated as "resin ■").

), (2) a resin containing a hydroxyl group, an epoxy group, a silanol group, and/or a hydrolyzable group directly bonded to a silicon atom (hereinafter abbreviated as "resin (2)"), and the like.

Resin ■: The hydroxyl group-containing resin (I) has an average of two or more hydroxyl groups in one molecule, and preferably has a number average molecular weight of 1.00.
0-200.000, preferably 3.000-80.0
00 can be used.

If the number of hydroxyl groups is less than 2 on average, the curability (gel fraction) will be poor, which is not preferable. The number of hydroxyl groups is preferably 400 or less on average from the viewpoint of finish quality, water resistance, etc. If the number average molecular weight is less than 1,000, physical properties (impact resistance), water resistance, etc. will be poor; 200
．． If it exceeds 000, the compatibility with other components will decrease, resulting in non-uniform curing and poor finish, which is not preferred.

As the hydroxyl group-containing resin (I), conventionally known resins can be used, but it is particularly preferable to use a vinyl polymer from the viewpoint of weather resistance, finishing properties, etc.

As the vinyl polymer, for example, a (co) polymer obtained by radical polymerization of the following hydroxyl group-containing polymerizable unsaturated monomer (a) and, if necessary, other polymerizable unsaturated monomers (b).
Polymers can be used.

Examples of the hydroxyl group-containing polymerizable unsaturated monomer (a) include (a-1) to (a-5).

(a-1) Hydroxyalkyl vinyl ether, hydroxybutyl vinyl ether, etc., (a-2) Allyl alcohol and methallyl alcohol, (a-3) Hydroxyalkyl ester of (meth)acrylic acid: hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, etc. (a-4) (poly)alkylene glycol monoacrylate Ethylene glycol monoacrylate, polyethylene glycol monoacrylate, etc. (a-5) (a-1) to ( a-4) and lactones (
For example, adducts with ε-caprolactone, γ-valerolactone), etc.

Examples of other polymerizable unsaturated monomers (b) include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, and lauryl (meth)acrylate. meth)acrylate, cyclohexyl(meth)
C+-i of (meth)acrylic acid such as acrylate
4 alkyl or cycloalkyl esters: Vinyl aromatic compounds such as styrene vinyl toluene, etc.: perfluorobutylethyl (meth)acrylate, perfluoroisononylethyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, etc. Examples include perfluoroalkyl (meth)acrylates and (meth)acrylonitrile, olefins, fluoroolefins, vinyl esters, cyclohexyl or alkyl vinyl ethers, aryl ethers, and the like.

The epoxy group-containing resin (n) has an average of 2 to 3 epoxy group-containing resins in one molecule.
00 epoxy groups, preferably a number average molecular weight of 120 to 200.000, preferably 240 to so, o
It belongs to oo. If the number of epoxy groups is less than 2 on average, the curability and impact resistance will be poor, which is undesirable, and it is difficult to obtain a compound with a number average molecular weight of less than 120. If it exceeds 000, the compatibility with other components will be poor, and as a result, the weather resistance, finishing properties, etc. of the resulting coating film will be deteriorated, which is not preferable.

As the epoxy group-containing resin (n), polyepoxide (
For example, a compound with a number average molecular weight of 2.000 or less containing at least two oxirane groups in one molecule described in JP-A-2-160879), an oxirane group-containing polymerizable unsaturated monomer (C) ( For example, JP-A-2-16087
Homopolymers of alicyclic vinyl monomers of general formulas (4) to (18) described in Publication No. 9) or copolymers with other polymerizable unsaturated monomers (b) described above are suitable. Can be used for

Examples of the resin (III) containing a silanol group and/or a hydrolyzable group directly bonded to a silicon atom include γ-
(meth)acryloxypropyltrimethoxysilane, γ
(meth)acryloxypropyltriethoxysilane, γ
(meth)acryloxypropyltrisilanol, γ-(
meth)acryloxypropylmethyldimethoxysilane,
Silane compound (d-1) such as vinyltrimethoxysilane, vinyltriethoxysilane, 2-styrylethyltrimethoxysilane, allyltriethoxysilane, etc.: The silane compound (d-1) and a trialkoxy or trihydroxysilane compound ( For example, reaction product (d-2) with methyltrimethoxysilane, phenyltrimethoxysilane, methyltrisilanol (for example, JP-A-2-1608
A homopolymer of the polysiloxane macromonomer (described in Japanese Patent No. 79) or a copolymer with other polymerizable unsaturated monomers (b) can be suitably used.

The blending ratio of the resins (I), (II), and (III) is 5 to 95% by weight of the resin (I) based on the total amount of these three components.
, preferably 20-80% by weight, resin (II) 95-5
% by weight, preferably 80-20% by weight, resin (III)
0. A range of 1 to 80% by weight, preferably 1 to 20% by weight is preferable from the viewpoint of curability and coating finish properties.

Resin ■: Epoxy group-containing resin (II), resin containing a silanol group and/or a hydrolyzable group directly bonded to a silicon atom (
As III), those similar to those mentioned above can be used.

In addition, in resin (■), resin (n) and resin (II)
As a method for introducing a hydroxyl group into the resin (II) and resin (III), for example, the hydroxyl group-containing polymerizable unsaturated monomer (a) may be used as a monomer component. ) as an essential monomer component.

In this case, the number of hydroxyl groups in one molecule is preferably 1 or more, preferably 400 or less on average, and the number average molecular weight of the resin into which hydroxyl groups are introduced is 1.
000-200.000, preferably 3.000-so
, ooo is desirable.

The blending ratio of the resins (n) and (+11) is 5 to 95% by weight, preferably 20 to 80% by weight of the resin (■) and 95 to 5% by weight of the resin (III) based on the total amount of these two components. , preferably in the range of 80 to 20% by weight from the viewpoint of curability and coating finish properties.6 The above-mentioned hydroxyl group-containing resin (I) can be blended with Resin (1) as needed.

Resin ■: The resin ■ has an average of 1 or more, preferably an average of 2 to 40, silanol groups and/or hydrolyzable groups directly bonded to silicon atoms in one molecule; Preferably 2 to 40 epoxy groups and an average of 2 to 2 in one molecule.
It is preferable to have 00 hydroxyl groups from the viewpoint of curability and coating film finish.

Resin (2) is, for example, the hydroxyl group-containing polymerizable unsaturated monomer (a
), the oxirane group-containing polymerizable unsaturated monomer (C),
The silane compound (d-1) and/or the reactant (d-2
), and a copolymer with other polymerizable unsaturated monomers (b) as necessary can be suitably used.

The blending ratio of the monomers (a) to (d-2) may be such that the functional groups in the resin fall within the above range.

In addition, the number average molecular weight of resin (■) is 1.000 to 200.00.
0, preferably 3,000 to so, ooo.

The hydroxyl group-containing resin (I) may be blended with resin (I) as required.

Examples of the base resin include hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and butyl acetate, ether solvents such as dioxane and ethylene glycol diethyl ether, It is used in the form of solution, dispersion, non-aqueous dispersion, etc. dissolved or dispersed in alcoholic solvents such as butanol and propatool, aliphatic hydrocarbons such as pentane, hexane, heptane, etc.

The non-aqueous dispersion type base resin composition uses the resin as a dispersion stabilizer, and in the presence of the dispersion stabilizer, one or more radically polymerizable unsaturated monomers and a polymerization initiator are added to the monomer. A non-aqueous dispersion can be produced by adding the monomer and dispersion stabilizer to an organic solvent in which the monomer and the dispersion stabilizer are dissolved, but in which the polymer particles obtained from the monomer are not dissolved, and a polymerization reaction is carried out. All of the monomers described above can be used to form the polymer that is the particle component of the non-aqueous dispersion. Preferably, the polymer serving as the particle component is a copolymer containing a large amount of highly polar monomer, since it must not be dissolved in the organic solvent used. Namely, methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylonitrile, 2-hydroxy (meth)acrylate, hydroxypropyl (meth)acrylate, (meth)acrylamide, acrylic acid,
It is preferable to contain a large amount of monomers such as methacrylic acid, itaconic acid, styrene, vinyltoluene, α-methylstyrene, and N-methylol(meth)acrylamide. Further, the particles of the non-aqueous dispersion can be crosslinked if necessary. An example of a method for crosslinking the inside of the particles is to copolymerize a polyfunctional monomer such as divinylbenzene or ethylene glycol dimethacrylate.

The organic solvent used for the non-aqueous dispersion does not substantially dissolve the dispersed polymer particles produced by the polymerization, but is a good solvent for the dispersion stabilizer and radically polymerizable unsaturated monomer. is included. In general, aliphatic hydrocarbons are preferably used in combination with aromatic hydrocarbons and alcohol-based, ether-based, ester-based, or ketone-based solvents as described above. Furthermore, trichlorotrifluoroethane, metaxylene hexafluoride, tetrachlorohexafluorobutane, etc. can also be used if necessary.

Polymerization of the above monomers is carried out using a radical polymerization initiator. Examples of usable radical polymerization initiators include azo initiators such as 2,2'-azoisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), benzoyl peroxide, and lauryl peroxide. Examples include peroxide-based initiators such as oxide and tert-butyl peroctoate, and these polymerization initiators are generally used within a range of 0.2 to 10 parts by weight per 100 parts by weight of monomers to be subjected to polymerization. The formulation of the dispersion stabilizer resin to be present during the above polymerization can be selected from a wide range depending on the type of the resin, but in general, a radically polymerizable inorganic resin is added to 100 parts by weight of the resin. Suitably, the amount of saturated monomer is about 3 to 240 parts by weight, or 5 to 82 parts by weight.

In the present invention, the dispersion stabilizer resin and the polymer particles can also be combined.

The non-aqueous dispersion resin composition described above is a non-aqueous dispersion in which a solid phase, which is a polymer particle formed by polymerizing a radically polymerizable unsaturated monomer, is stably dispersed in a liquid phase in which a dispersion stabilizer resin is dissolved in an organic solvent. It is a dispersion liquid that can significantly increase the solid content during coating, and also increases the viscosity after coating, so it does not cause sagging,
It is possible to form a film with excellent finished appearance and no run-off. Furthermore, the formed film is a light and chemically stable film in which the continuous phase of the film has an organic silane group, and furthermore, the polymer particle components in the film are stabilized by the continuous phase, and the film is stable. Since the particles are reinforced by the particle component, a film with excellent mechanical properties such as impact resistance can be formed.

The curing catalyst used in clear paint compositions is used to promote the reaction of silane groups, epoxy groups, and hydroxyl groups in the resin. metal alkoxides bound to; metal chelate compounds in which the metal alkoxides are coordinated with a chelate compound capable of forming a keto-enol tautomer; AεCI;
2. , A! (CxHs)zcε, T ICA 4,
Z r CI24, S n C124F e
CI24, BFs, BP: (OC, H,).

Lewis acids such as: organic protonic acids (metasulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, etc.), inorganic protonic acids (phosphoric acid, phosphorous acid, phosphinic acid, sulfuric acid, etc.); aluminum silicate, etc. Compounds having a 5i-0-Aε bond such as the following can be suitably used. Among the above, metal chelate compounds are preferred, and furthermore, diisopropoxyethylacetoacetate aluminum, tris(ethylacetoacetate) aluminum, isopropoxy bis(ethylacetoacetate) aluminum, monoacetylacetonate bis[ethylacetoacetate) aluminum , tris(n
-propylacetoacetate) aluminum, tris(
n-butylacetoacetate)aluminum, monoethylacetoacetate/bis(acetylacetonato)aluminum, tris(acetylacetonato)aluminum, tris(propionylacetonate)aluminum, acetylacetonate/bis(propionylacetonate)aluminum, etc. Aluminum chelate compounds such as diisopropoxy bis(ethylacetoacetate titanium, diisopropoxy bis(acetylacetonate) titanium, etc.) titanium chelate compounds such as tetrakis(n-propylacetoacetate) zirconium, tetrakis(acetylacetonate) ) Zirconium chelate compounds such as zirconium, tetrakis(ethyl acetoacetate) zirconium, etc. are suitable.

The blending ratio of the curing catalyst is based on 100 parts by weight of the resin.
The amount is 0.01 to 30 parts by weight, preferably 0.1 to 10 parts by weight. If the curing catalyst is less than 0.01 parts by weight, the curability will decrease, and if it exceeds 30 parts by weight, the water resistance of the coating will decrease, so it is not preferred.

The clear paint composition may contain ultraviolet absorbers, antioxidants, light stabilizers, and various other paint additives, if necessary. In addition, coloring pigments, extender pigments, and the like may be added to the composition to the extent that the transparency of the clear top coat is not impaired.

In the method of the present invention, for example, a chemical conversion treated steel plate is coated with an electrodeposition paint, an intermediate coat (sometimes omitted) is applied, and a brimer suitable for various plastic materials is applied. This can be carried out by using a coating film coated with (in some cases) as a material, coating it with a colored coating composition, and then coating it with a clear coating composition. The above electric paint and intermediate paint are usually baked at 140 to 190°C for 30 to 90 minutes, although this varies depending on the type of paint. The colored and clear coating compositions can be applied using conventional coating methods, such as electrostatic coating or non-electrostatic coating equipment. In addition, the film thickness of the colored base coat is 10~
Approximately 50 houses (after curing) is preferable. After painting, the paint is left at room temperature for several minutes, forced drying at about 50 to 80 degrees Celsius for several minutes, or heated (heating is at 130 degrees Celsius for 30 minutes to 19 minutes).
After curing (which may take about 10 minutes at 0°C), a clear paint composition is applied. The thickness of the clear coating is 20~tooP
(after curing) is preferred. Next, the object to be coated is heated to 60 to 170
It can be cured by heating at about 10°C for about 10 to 90 minutes.

The present invention uses a coating film made of a specific composition as a colored base coat and a clear top coat, so that it can exhibit the following excellent effects. As a result, there is no risk of changing the slam control of the metal flakes or mica powder in the colored pace coat (uneven metallic return, etc.), so it is possible to form a multi-layer topcoat film with excellent cosmetic properties.

(2) Since no wrinkles occur in the coating film during curing, a coating film with excellent finished appearance can be obtained.

(3) Excellent interphase adhesion between the colored base coat and the clear top coat. Therefore, a coating film suitable for recoatability and two-coat/two-bake coating methods can be formed.

(Example) Next, the present invention will be described in detail by giving Examples, but the present invention is not limited thereto.

"Parts" and "%" in Examples and Comparative Examples are based on weight.

Example 1 45 parts of isopropyl alcohol is placed in a four-bottle flask and heated to 80°C. To this was added a mixture of 5 parts of acrylic acid, 25 parts of hydroxyethyl acrylate, 10 parts of ethyl acrylate, 30 parts of butyl acrylate, 30 parts of styrene, and 1 part of 2,2'-azobis(2,4-dimethylvaleronitrile). A mixture of 3 parts of isopropyl alcohol was added dropwise in parallel over a period of 3 hours under a nitrogen atmosphere, and aged for 15 hours after the completion of the 0 drop, a mixture of 0.5 parts of 2,2'-azobis(2,4-dimethylvaleronitrile, 2 parts of isopropyl alcohol) is added dropwise over 1 hour. After further aging for 1.5 hours, the acid value is 40, the hydroxyl value is 121, and the number average molecular weight is 30.0.
A base resin of No. 00 was obtained. To this was added 20 parts of a toluene solution of 30 parts of trimethylolbroban trignosidyl ether and 2 parts of aluminum acetylacetonate to obtain the organic solution-form composition of Example 1. Next, this was spread on a tin plate to a thickness of about 30 mm. It was applied so as to form a web and heated at 160° C. for 30 minutes to obtain a coating film with a gel fraction of 92% and excellent solvent resistance and bending resistance. Moreover, the composition was stable (sedimentation, separation, etc.) for more than 3 months at room temperature.

Example 2 8.1 parts of 30% ammonia water was added to the composition of Example 1, and deionized water was added while stirring to obtain an aqueous dispersion of Example 2 with a resin content of 30%. was spray-painted on a tin plate, dried at 80℃ for 10 minutes, and then heated to 160℃.
Baked for 30 minutes, thickness 25μ, hardness H, gel fraction 9
A coating film with excellent solvent resistance and bending resistance of 1% was obtained. Further, the aqueous dispersion was stable (sedimentation, separation) for more than one month at room temperature.

Example 3 Aluminum acetylacetonate 2 in Example 1
20 parts of tetraethylammonium hydroxide instead of
The organic solution type composition of Example 3 was obtained using the same formulation as Example 1 except that 19.5 parts of % methanol solution was used. 6 Next, this was applied to a tin plate and baked at 160°C for 30 minutes. A coating film having a thickness of 40 mm, a gel fraction of 90%, and excellent solvent resistance and bending resistance was obtained. The composition was stable at room temperature for more than 3 months (1 separation of sedimentation, etc.).

Example 4 8 parts of 30% ammonia water was added to the composition of Example 3, and deionized water was added while stirring to obtain a water dispersion of Example 4 with a resin content of 30%. Apply, 16
By baking at 0°C for 30 minutes, a coating film having a thickness of 401ffi, a gel fraction of 90%, and excellent solvent resistance and bending resistance was obtained. The composition was stable (no sedimentation, separation, etc.) at room temperature for more than 3 months.

Comparative Example 1 A composition was obtained in the same manner as in Example 1 except that the acrylic acid in Example 1 was changed to ethyl acrylate.6 Next, a coating film was prepared from this composition in the same manner as in Example 1. . As a result, both solvent resistance and bending resistance were poor with a gel fraction of 76%.6 Pressure resistance: 1 to 2
Fold in seconds. Items with no abnormalities such as peeling or cracking of the paint film on the bent part were considered to have passed.

Gel fraction: Peel off the dried coating film, place it in a 300 mesh stainless steel mesh container, extract with a Soxhlet extractor using acetone/methanol = 1/1 solvent at reflux temperature for 6 hours, and then The gel fraction was calculated according to the formula.

Gel fraction (%) = (Coating film weight after extraction/Coating film weight before extraction) xlOO Colored base paint 1 Aluminum paste 1109MA (
Product name, Toyo Aluminum ■, hereinafter the same meaning,
) was blended in an amount of 15 parts with respect to 100 parts of the cured resin composition in the paint, and further diluted with Kijiroll to obtain the paint 1 having a solid content of 30%.

Colored base paint 2 15 parts of aluminum paste 1109MA was blended with the paint composition of Example 3 based on 100 parts of the cured resin composition in the paint, and further diluted with Kijiroll to obtain paint 2 with a solid content of 30%. .

Clear Paints 1 to 5 Clear paints were obtained using the resins and catalysts shown in Table 1.

Resin composition■ (Part) Methyltrimethoxysilane 2720γ-Methacryloxypropyltrimethoxysilane 256 Deionized water 113430% Hydrochloric acid
2 Hydroquinone
The mixture was reacted at 80° C. for 5 hours to obtain a bossiloxane macromonomer. The macromonomer had a number average molecular weight of 2,000, and had on average one vinyl group (polymerizable unsaturated bond) and four hydroxyl groups per molecule.

(Part) Polysiloxane macromonomer 1002-Hydroxyethyl acrylate 1003.4 Epoxycyclohexylmethyl methacrylate 2002-Ethylhexyl methacrylate 500 Styrene
A mixture of 100 and 50 parts of azobisisobutyronitrile was added dropwise to 1.000 parts of an equal weight mixture of butanol and xylene at 120°C to obtain resin composition (2). The number average molecular weight of the resin is approximately 10.000
Met.

Resin composition (parts) γ-methacryloxypropyltrimethoxysilane 100 2-hydroxyethyl methacrylate 100 3.4 epoxycyclohexyl methacrylate 200 lylate 2-ethylhexyl methacrylate 500 styrene 100 azobisisobutyronitrile A mixture of 50 and 50 is mixed with butanol. This was added dropwise to 1.000 parts of an equal weight mixture of xylene at 120°C to obtain a resin composition (2). The number average molecular weight of the resin was approximately 9.000.

Resin composition (1) A mixture of the polysiloxane macromonomers 2-hydroxyethyl acrylate 2-ethylhexyl methacrylate styrene azobisisobutyronitrile (6 parts) was mixed with an equal weight mixture of butanol and xylene (1.0 parts).
00 parts at 120'C to obtain a resin composition (2). The number average molecular weight of the resin was approximately 10.000.

Resin composition (part) γ-methacryloxypropyltrimethoxysilane 2002-hydroxyethyl methacrylate 1002-ethylhexyl methacrylate 500 styrene
200 Azobisisobutyronitrile
50 was added dropwise to 1.000 parts of an equal weight mixture of butanol and xylene at 120°C to form a resin composition
I got it. The number average molecular weight of the resin was approximately 9.000.

Resin composition ■ (parts) 3.4 Epoxycyclohexyl 400 methacrylate 2-hydroxyethyl methacrylate 1OO2-ethylhexyl methacrylate 400 styrene
A mixture of 100 and 50 parts of azobisisobutyronitrile was added dropwise to 1.000 parts of an equal weight mixture of butanol and xylene at 120°C to obtain resin composition (2). The number average molecular weight of the resin is approximately 9.00
It was 0.

Resin composition (part) 2-hydroxyethyl methacrylate 1002-ethylhexyl methacrylate 400 styrene
100 methyl methacrylate
400 Azobisisobutyronitrile
A mixture of No. 50 and No. 50 was added dropwise to 1.000 parts of an equal weight mixture of butanol and xylene at 120°C to obtain resin composition (2). The number average molecular weight of the resin was approximately 9.000.

Table 1: Preparation of coated plate Apply epoxy resin-based cationic electrodeposition paint to a steel plate (chemical conversion treatment). Co., Ltd., polyester resin/melamine resin-based automotive paint) was applied to the surface to give a dry film thickness of 3C)p+++, and baked at 170°C for 30 minutes. Next #40
The painted surface was sanded with sandpaper, drained and dried, and the painted surface was wiped with petroleum benzene.

The paint was air sprayed, and in the case of 2CIB metallic, the 2CIB base coat was applied for 3 minutes, and then the 2CIB clear coat was applied immediately. The dry film thickness was 15 to 20 threads and 35 to 45 threads, respectively. Then, leave it at room temperature for 10 minutes and then heat it at 150°C for 30 minutes (but
Recoatability was determined by baking at 160°C for 30 minutes.

The coating performance and appearance are shown in Table 2.

Table-2 (Product name, manufactured by Kansai Paint Company, Min resin type) acrylic mela Test method (*1) Appearance: Checked for wrinkles and wrinkles in the paint film.

O No abnormality, O Slightly observed, × Many observed.

(*2) Image clarity and clarity measuring device fIMAGE CLAR
It was measured using ITYMETER (manufactured by Suga Test Instruments).

The numbers in the table are ICM values in the range of 0 to 100%, the higher the number, the better the image clarity (image clarity), and if the ICM value is 80 or higher, the image clarity is extremely excellent. Show that.

(*3) Metallic feel: Visually evaluated the gleam and whiteness of the metal when viewed from the front. 60 gleam, white, △ No gleam, poor whiteness, × No gleam at all, There is no whiteness at all.

(*4) Water resistance: After immersing a sample coated plate in 40°C warm water for 240 hours, the state of blistering on the coated surface was visually evaluated. 0 No abnormality, △ Slightly observed, × Significantly observed.

(*5) Recoatability: Coating the same base paint and clear paint as in the examples and comparative examples on the surface of the coating film at 160°C.
A coating film was obtained by baking for 30 minutes. Make a cross cut in the resulting coating film with a utility knife, apply cellophane tape to the coating surface, and then quickly peel it off to remove the space between the first and second coating (
The adhesion of clear coating film/base coating film was evaluated. 0 (No peeling observed, △ Slight peeling observed. × Significant peeling observed.

Claims (2)

[Claims] (1) The following components (A) base resin containing hydroxyl and carboxyl groups, (B) aliphatic polyepoxide curing agent, and (C) metal/β-diketone chelate and/or quaternary ammonium hydroxide catalyst as a cured resin composition. A coating composition comprising: (2) In a top coat multi-layer coating formed by sequentially forming a colored base coat and a clear top coat on a material, the colored base coat is combined with the following components (A) a base resin containing hydroxyl and carboxyl groups (B) an aliphatic polyepoxide curing agent (C). ) a catalyst of metal/β-diketone chelate and/or quaternary ammonium hydroxide; and (D) a colored pigment of metal flake powder and/or mica powder as essential components; The top coat is made of the following ingredients: (E) a base resin containing at least one group selected from silanol and a hydrolyzable group directly bonded to a silicon atom, a hydroxyl group and an epoxy group, and (F) a clearing agent whose essential components are a curing catalyst. A method for forming a coating film, characterized by forming the coating film using a coating composition.